Alkaline earth and amine salts of phosphate ester surfactants in dry cleaning compositions

ABSTRACT

DETERGENT COMPOSITION ADAPTED FOR INCORPORATION INTO A DRYCLEANING SOLVENT CONSISTING ESSENTIALLY OF A MIXTURE OF (A) THE SUBSTANTIALLY NEUTRAL AKLALINE EARTH METAL SALT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF PHOSPHORIC ACID ESTERS OF OXYETHYLATED HIGHER ALKYL PHENOL AND PHOSPHORIC ACID ESTERS OF OXYETHYLATED HIGHER ALIPHATIC MONOHYDRIC ALCOHOLS, SAID OXYETHYLATED ESTERS CONTAINING FROM ABOUT 1 TO 15 OXYETHYL GROUPS, AND SAID ALKALINE EATH METAL BEING SELECTED FROM THE GROUP CONSISTING OF CALCIUM, MAGNESIUM, AND THE MIXTURES THEREOF, AND (B) THE SUBSTANTIALLY NEUTRAL LOWER ALKYLAMINE AND LOWER ALKANOLAMINE SALT OF SAID PHOSPHORIC ACID ESTERS.

United States Patent ALKALINE EARTH AND AMINE SALTS OF PHOS- PHATE ESTER SURFACTANTS IN DRY CLEAN- ING COMPOSITIONS Clayton A. Wetmore and Edwin B. Michaels, Fairfield, Conn., assignors to Stamford Chemical Industries, Inc., Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Sept. 2, 1966, Ser. No. 576,814

Int. Cl. Clld 1/34, 1/78, 3/44 U.S. Cl. 252-152 1 Claim ABSTRACT OF THE DISCLOSURE This invention relates to novel drycleaning detergent compositions. More particularly, it relates to detergent compositions adapted for incorporation into a drycleaning solvent, comprising a mixture of (a) the alkaline earth metal salt, for example, the magnesium or calcium salt, of a substantially neutral phosphate ester and (b) the lower alkyl amine or lower alkanol amine salt of a substantially neutral phosphate ester, herein below defined.

It is known that the salt of neutral monoor di-phosphoric .acid esters of oxyethylated higher alkyl phenols or aliphatic monohydric alcohols does enhance the detergency and soil dispersion properties of a highly polar organic drycleaning solvent, such as perchloroethylene, when incorporated therein. However, the salt additive is compatible in and limited to an organic polar solvent. Further, the salt additive imparts relatively poor water solubilizing properties to the polar drycleaning solvent. As is also known, it is an important attribute of a detergent additive in a dry cleaning solvent-charge system to impart water solubilizing characteristics, for otherwise the presence of excess water can irreparably damage a garment.

In a copending application, Ser. No. 289,716, filed June 21, 1963, now abandoned, there is disclosed a mixture of the magnesium salt of a substantially neutral phosphate ester and the amine salt of certain alkyl aryl sulfonic acids so as to additionally impart water binding properties to a polar solvent while simultaneously leaving unaffected the good detersiveness of the magnesium salt. Unfortunately, such a mixture is entirely heterogenous and unstable for prolonged periods, separating into undesirable layers upon standing. Thus, turbidity is imparted to a polar sol- 3,562,168 Patented Feb. 9, 1971 "ice vent and is substantially incompatible in non-polar solvents at any relative humidity level.

It is a primary object of the invention to provide a detergent additive composition which exhibits increased detersiveness, increased water-solubilizing or water-binding properties, stability and compatibility in non-polar as well as polar drycleaning solvents. It is a further object to provide a detergent mixture comprising either a magnesium or a calcium salt of a neutral phosphate ester and an amine salt of a neutral phosphate ester, both salts defined below, which mixture substantially overcomes the shortcomings of the prior art. Other objects and advantages will be readily ascertained from the following detailed description.

It has been unexpectedly found that the above objects can be achieved by incorporating into a drycleaning solvent, such as a highly polar organic solvent or a nonpolar organic solvent, a mixture of approximately equal parts by weight of (a) a magnesium or calcium salt of a neutral phosphoric acid ester of oxyethylated higher alkyl phenols or aliphatic monohydric alcohols and (b) an alkyl amine salt or an alkanol amine salt of a neutral phosphoric acid ester of oxyethylated higher alkyl phenols or aliphatic monohydric alcohols. In the composition of the invention the magnesium or calcium salt characterized by its low water-binding property is surprisingly enhanced by the addition thereto of the aforementioned lower alkanol amine or lower alkyl amine salt to impart stability and compatibility to any drycleaning solvent, while maintaining a high level of detergency therein.

Magnesium or calcium salts of the aforementioned neutral phosphoric acid esters are prepared in a straightforward manner. In general, about one mol of either a higher alkyl phenol or a higher aliphatic monohydric alcohol is reacted with from about one to about fifteen mols of ethylene oxide. It is a good practice, however, to react from about 1.5 to about 6.0 mols of ethylene oxide per mol of higher alkyl phenol or higher aliphatic alcohol. Mixtures of such oxyethylated phenols or alcohols are also contemplated. Thus, for example, a substantially mono-oxyethylated phenol, prepared by reacting nonyl phenol with one mol of ethylene oxide, can be admixed in equal proportions with a polyoxyethylated phenol, such as nonyl phenol, reacted with about eight mols of ethylene oxide.

Illustrative higher alkyl phenols or higher aliphatic monohydric alcohols are: o-octyl phenol, o,p-dioctyl phenol, p-nonyl phenol, o-p-dinonyl phenol, tridecyl phenol, octyl alcohol, decyl alcohol, lauryl alcohol and tridecyl alcohol. Since the octyland nonyl phenols are readily commercially available, they constitute preferred reactants.

Oxyethylated higher alkyl phenols or oxyethylated higher aliphatic monohydric alcohols are next reacted in any suitable closed reaction vessel with phosphorous pentoxide at temperatures between about C. and about 140 C., and preferably from C. to C., for from about 5 to 250 hours, or more. Usually from about two and one-half mols to five mols, and preferably from 3.5 to 4.5 mols, of the phenol or alcohol reactant per mol of phosphorous pentoxide are sufiicient to effect the desired reaction.

It is found that the foregoing phosphoric acid synthesis results in a mixture of monoand di-phosphoric acid esters which can, if desired, be separated. It has been observed that a mixture of mono-and di-ester is highly useful as the detergent in a mixture with the highly polar drycleaning solvent. Esters of complex phosphoric acids can also be formed. However, they can be hydrolyzed to the phosphate esters and to insure that a mol ratio of diesters to mono-esters in said ester mixture be present in the range of from 1 to 1 or greater, respectively. It has been further found that the mol ratio range of di-ester to mono-ester will widely vary from about 1:0.5 to 1:20 or greater, and preferably from 1:1 to 1:4 respectively, as determined by electrometric titration. In general, the phosphate esters are titrated in an aqueous medium with standard alkali. Two endpoints are obtained. The first endpoint, termed (H reflects the hydrogen ion of the di-ester and the first hydrogen ion of the mono-ester. The second endpoint, termed (H reflects the second hydrogen ion of the mono-ester. The ratio can be expressed as follows:

Mols of di-ester (2a-b) Mols of mono-ester (b-a) in which a is defined as the total number of milliliters of alkali necessary to attain an endpoint or pH of H (usually pH=3-6), and b is defined as the total number of milliliters of alkali to attain an end point of pH of H (usually pH:8-9).

Variations in the mol ratio of dito mono-esters prior to reaction with either a magnesium or calcium base is, for instance, dependent upon the phosphorous pentoxide to the phenol or alcohol mol reaction ratio, Additionally, time and temperature are factors which can affect the mol ester ratio. Thus, for instance, either where the mol ratio of the alcohol or phenol reactant to phosphorous pentoxide is about 4:1, but the time employed during the reaction is excessively long, say 14 days or more, or where temperatures are excessively high, say in excess 140 C., polymeric complex phosphoric acid esters, such as esters of pyrophosphoric acid, are formed. Under the latter re action conditions, the mol ratio of di-ester to mono-ester of resultant phosphate ester is less than 1:1, and usually about 1:0.5.

Notwithstanding polymeric complex phosphoric acid ester formation, such complex can be converted unexpectedly to useful phosphate esters of enhanced detergency by hydrolyzing the polymeric complex prior to salt formation. The hydrolysis is accomplished by adding Water from 5% to or more, based on the weight of the polymeric complex, and heating the mixture to from about 80 C. to 120 C. for from about one to about twenty-four hours. When hydrolysis takes place, and for good practice should be effected if the acid number of hydrolyzed ester increases 1% or more, pH titration measurements are taken to determine the mol ratio of resultant esters. It is found that the mol ratio of diester to mono-ester is increased respectively from less than 1:1 to from 1:1 to 1:2.

As the salt neutralization step in the preparation of the hydrophobic phosphoric acid ester salt, a magnesium base, calcium base or mixture thereof, such as magnesium oxide, magnesium hydroxide, calcium oxide or calcium hydroxide and the forementioned phosphoric acid ester are admixed either in an aqueous medium or in an aqueous alcoholic medium. The latter mixture is agitated for from about one-half hour to two hours. The pH of the reaction mixture is intermittently tested. For instance, when a pH of 6 to about 8 is obtained, the reaction is then deemed to be completed and the reaction solvent removed to recover resultant magnesium or calcium salt.

Similarly, the hydrophilic amine salt of the herein 4 above described phosphoric acid ester is formed by admixing a lower alkylamine or lower alkanol amine with the said ester until a pH between about 6 and 8 is obtained.

Illustrative amine reactants are, for instance: mono ethanolamine, diethanolarnine, triethanolamine, diisopropanolamine, monoisopropanolamine, n butanolamine, monoisopropylamine and tertiary butylamine. As a specific embodiment, the amine salt is prepared by adding sufficient mine reactant to the phosphate acid ester so as to reach a pH of approximately 7. The neutralization reaction is exothermic and is, therefore, carried out at room temperature by slowly adding the amine or in a cooling vessel whereby the amine may be added at a more rapid rate. The amine salts are readily prepared and are clear viscous liquids ranging in color from colorless to amber. These salts possess Water-binding properties but demonstrate poor detergency and high soil redeposition. However, for the purpose of handling them easily, they are dissolved in petroleum ether or in deodorized kerosene.

Alternatively, mixtures of both the calcium or magnesium salt and the amine salt of the same phosphoric acid ester may be prepared concurrently prior to incorporation into a desired highly polar or non-polar solvent. However, in any event, mixtures of magnesium or calcium phosphates and amine phosphates as concentrates, employed in ratios from 1:01 to 1:2, respectively, are substantially homogeneous and stable.

Any commercially available highly polar or non-polar drycleaning solvent is within the purview of the instant invention. Illustrative solvents are: benzene, petroleum ether, perchloroethylene and trichloroethylene. A good practice is to add a magnesium or calcium phosphate and an amine phosphate mixture described above to any one of the drycleaning solvents in amounts ranging from about 0.2% to about 4% of said salt, based upon the weight of the solvent.

To facilitate an understanding of the invention, the following examples are given as merely illustrative of the best practices herein and are not to be taken as limiting the same. The parts given are by weight.

The preparation of the magnesium or calcium salts of substantially neutral phosphate monoand di-esters is illustrated below:

EXAMPLE A Into a suitable pressure vessel is added one mol of phosphorous pentoxide and four mols of polyoxyethylated nonylphenol containing an average of 5.5 oxyethyl groups. The vessel is next sealed and heated to about 99 C. for 168 hours. Heating is discontinued, the reaction vessel opened and the contents therein are slowly cooled to room temperature and removed from the reaction vessel.

A small amount of the reaction product is analyzed to determine the type of ester present. It is found that the acid number of reaction product is 81.8 and consists of diand mono-esters in a mol ratio of 1 to 1.5 respectively.

1000 parts of the esters so prepared (one mol) and 30 parts of magnesium oxide (0.75 mol) are stirred in a suitable vessel containing 40 parts of water, parts methyl amyl alcohol for about one hour. The pH of the resultant paste, when diluted with water for testing, is 7.0. A clear opalescent paste, dispersible in water andsoluble in perchlorothylene is obtained.

EXAMPLE B Example A is repeated in every material respect, except that polyoxyethylated octyl phenol containing an average of 3.5 oxyethylated groups is substituted for the polyoxyethylated nonyl phenol reactant. On titration, the mol ratio of di-ester to mono-ester in the ester composi tion is 1 to 1.1 and the acid number is 100.8.

The magnesium salt of phosphoric acid ester is prepared as in the preceding example. Resultant salt is characterized as being relatively insoluble in water and more efficient in emulsifying petroleum sol-vents than the higher ethoxylated salt of Example A, above.

EXAMPLE C Example A is repeated in every material respect except that calcium oxide is substituted for magnesium oxide and possesses the same solubility characteristics as exhibited by the magnesium salt.

'EXAMPLE D Example B is repeated in every material detail except that the calcium salt is prepared by replacing the magnesium oxide with calcium oxide, Resultant salt is soluble in kerosene and insoluble in water. The calcium salt is a hard waxy solid.

The following examples are illustrative of the amine salt formation.

EXAMPLE E Suflicient diethanolamine is added to the phosphate ester per se as prepared in Example A until a pH of approximately 7 is attained. The reaction is carried out at room temperature and resultant product is recovered as a clear, viscous hydrophilic liquid.

EXAMPLE F Repeating the procedure of Example E in every detail except monoisopropanol amine is substituted for the diethanol amine therein. There is obtained a substantially amber colored viscous hydrophilic liquid.

EXAMPLE G To a suitable reactor is added suflicient monoisopropylamine and the phosphate ester per se as prepared in Example B until a pH of approximately 7 is noted. The reaction is exothermic and continues until an amber colored, viscous hydrophilic liquid is obtained.

EXAMPLE H Suflicient diethanolamine is added to the phosphate ester per se as prepared in Example B above until neutrality (pH 7) is achieved. The temperature of reaction is approximately maintained at about 40 C. Resultant product is recovered as a substantially amber colored viscouse hydrophilic liquid.

EXAMPLE I Example H is repeated in every detail except that monoisopropanol amine is substituted for the diethanolamine reactant to recover the corresponding monoisopropanol amine of the phosphate ester.

EXAMPLE I This example illustrates the in situ preparation of a magnesium and amine salt of the same phosphate ester to 100 parts of tridecyl alcohol-ethylene Oxide condensate prepared by reacting 1 mol of the alcohol with six mols of ethylene oxide, are added 5.2 parts of phosphorous pentoxide while stirring in a suitable reaction vessel at a temperature of from about 50 C. to about 55 C., until all the phosphorous pentoxide is dissolved therein. The temperature is next increased to about 96 C. and heated for a period of 170 hours. On titration the di-to mono-ester mol ratio of the ester composition is 1 to 1.8 and the acid number is 96.3.

The reaction product obtained is cooled to room temperature and to the clear viscous liquid is added a mixture of 8 parts (by volume) of methyl amyl alcohol and 4 parts water.

To the aforementioned mixture is simultaneously added one and one-half parts of lightly precipitated magnesium oxide and one and half parts of diethanolamine. The mixture is stirred until a pH of 7.1 is noted in testing as an aqueous dispersion. A substantially opalescent homogeneous, stable paste, dispersible in 'Water and soluble in perchloroethylene or petroleum ether is obtained.

To demonstrate that the above exemplified magnesium or calcium salts are valuable detergent adjuvants in highly polar and non-polar drycleaning solvents, each of the salts is separately admixed with a lower alkylamine salt or a lower alkanol-amine salt of the phosphoric acid ester and tested in the following manner.

Enhanced detersive properties of the compositions illustrated in the table below are determined in the conventional manner involving the use of a launderometer as described in the AATCC yearbook for 1955 at page 55 following. In a typical run a standard soiled swatch and stainless steel balls together with the highly polar drycleaning solvent containing 1% by weight of the detergent additive mixture are added to a launderometer jar. After a twenty minute Wash cycle, the washed swatch is removed from the jar, and dried to remove the solvent. Reflectance readings before and after washing of the soiled and unsoiled swatches are taken and recorded in percent detergency and percent redeposition respectively. In the illustrative examples below, the initial reflectance readings of the cotton and W001 swatches used are: 96 and 92, respectively; the soiled swatches for cotton and wool are 30 and 28 respectively. Percent detergency is determined by subtracting the reflectance reading of the soiled swatch and dividing this difference by the difference between the initial unsoiled swatch reflectance reading and the soiled reflectance reading, multiplied by 100. Thus, for instance, the percent detergency for cotton is:

where R is the reflectance reading of the soiled swatch after drycleaning whereas the percent redeposition for cotton is similarly represented by the formula:

where R is the reflectance reading of unsoiled swatches after drycleaning. In the examples below the percent detergency and percent redeposition are determined in perchloroethylene Perc.) or petroleum ether solvent.

In the examples below illustrative over-all detergent compositions of calcium salts, magnesium salts, or mixtures thereof and amine salts are prepared.

EXAMPLE 1 To the product of Example A above is added an equal amount by weight of the diethanolamine salt of Example E above to obtain an amber paste. This mixture is dil-uted with an equal amount of deodorized kerosene forming an amber viscous liquid as a concentrate to facilitate handling. The latter is homogeneous and stable over a prolonged period of time.

EXAMPLE 2 Substituting for the amine salt in Example 1 above, monoisopropanolamine salt of Example F above, a composition possessing substantially the same enhanced detergency is obtained. The mixture is homogeneous and stable.

EXAMPLE 3 To the product of Example A above dissloved in petroleum ether is added an equal amount of by weight of the monoisopropylamine salt of Example G above. This mixture is homogeneous and stable.

EXAMPLE 4 To the product of Eaxmple B above is added to an equal amount by weight of the monoisopropanolamine salt of Example I above. An equal amount of petroleum ether is added to this mixture to facilitate handling. A stable and homogeneous mixture is obtained.

P weight of the solvent and teste and wool swatches having tive humidity as measured by conductivity measurements are also presented.

issolved in EXAMPLE 5 To the product of Example B above (1 petroleum ether is added an equal amount by weight of the monoisopropylamine salt of Example G above to obtain a homogeneous mixture.

EXAMPLE 6 Equal weights of salts prepared in Examples C and E,

Detergent sitionS of the invenlvents.

ain substantially clear and 1c acid ester of Advantageously, the compositions may be prepared horic acid ester in non-polar drycleaning so they maintain substantia longed period of time.

1. A detergent composition consisting essentially of (a) the substantially neutral calcium salt of phosphoric acid taining an average bstantially neutral ine salt of phosphor enol containing an average of 3.5

rapidly by neutralizing the same phosp with diverse cations to form the novel compo invention in situ. The compositions of the present 65 tion can be employed Further, as concentrates stability in that they rem homogeneous over a pro We claim: D and I 70 d as a viscous, amber This mixture is stab ester of oxyethylated octyl phenol con of 3.5 oxyethyl groups and (b) the su inmonoisopropanol am or 75 oxethylated octyl p11 above, in equal weight s an amber,

The latter is stable and 1e and homo- EXAMPLE 8 petroleum solvents a 'd concentrate mixture.

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above, in 50% petroleum ether are an amber, viscous liquid mixture whic and stable.

An equal we above,

viscous liquid concentrate. This concentrate is stable and homogeneous.

The salts of Examples D and E are prepared in 50% viscous liqui homogeneous.

A mixture of salts prepared in Examples B above, in equal we liquid concentrate. geneous.

Each of the above detergent compositions is corporated into either perchloroethylene solvent oxyethyl groups, said calcium salt to said amine salt being present in a ratio of 1:1 by weight, rwpectively.

References Cited UNITED STATES PATENTS 10 FOREIGN PATENTS 3/1961 France 260--950X OTHER REFERENCES GAFAC Phosphate Ester Surfactants as Drycleaning Detergents, published by General Aniline & Film Corp.,

Edwards 8142 Smith et a1. 252161 1963 (13 Pages f Nmm LEON D. ROSDOL, Primary Examiner Ernst et a1 252152 Michaels 10 D. L. ALBRECHT, Assistant Examlner Segan 260-925 Young U-s- C1- Fetch 260-961 8-142; 25289, 153, 171, 172 Alphonse 252161 

